Power consumption is one big advantage of the MiST over original hardware and even PC emulators.

Only the Raspberry Pi gets close, but I still find it much more cumbersome to setup RetroPie than an SD card for the MiST. With some cores you can even use the same SD cards between the MiST and real hardware (e.g. a Spectrum with DivIDE or a console with an Everdrive).